[A case with polyarteritis nodosa associated with acute renal failure and pericardial cyst].

Polyarteritis nodosa (PN) is a disease characterized by vasculitis of multiple organs, and it is complications of kidney and heart are fatalistic factor. Myocardial infarction and pericarditis are well known as cardiac involvement of PN. The pericardial cysts are uncommon disease and it originated in the mesenchymal tissue during fetal life. There has been no report that pericardial cyst undergoing with PN. The present paper was the first report about case with enlargement of pericardial cyst caused by vasculitis. A 64-years old female was referred for acute renal failure and mediastinal tumor. The diagnosis of PN was confirmed with the renal biopsy showing the typically histological features of necrotizing angitis, renal angiography showing vascular irregularity in the renal arterioles and clinical features such as fever, hypertension and skin lesion. The mediastinal tumor was identified with enlargement of pericardial cyst diagnosed by computer tomography (CT) and magnetic resonance imaging (MRI), and ultrasonic cardiography (UCG) revealed pericardial effusion. Enlargement of pericardial cyst, pericardial effusion and acute renal failure were due to vasculitis as a partial manifestation of PN. Under the steroid administration, sequentially recovery of renal function and disappearance of pericardial cyst and pericardial effusion were observed.